The invention relates to an anti-skid device for motor vehicles, with a plurality of chain lines which are fastened to a holder capable of being set in rotational movement by the vehicle tire and of which the ends facing away from the holder, with the holder rotating in the operating position, are thrown away from the holder under the effect of centrifugal force into the region of the ground contact surface of the rotating vehicle tire, with a pivoting unit which is arranged on a carrying part fastened to the vehicle and having a cavity and which is intended for a jib arm carrying the holder, and with means for introducing oppositely directed pivoting movements into the pivoting unit, by which means the jib arm can be moved out of its position of rest into its operating position and back.
An anti-skid device of the foregoing type is known from DE,3645,126 C2. In the known device, the carrying part is formed by a carrier tube which, for positioning purposes, is displaceable to and fro and is pivotable about its longitudinal axis. On one end of the carrying part, the latter carries a pivoting unit, driveable by a flexible shaft and designed as a worm gear, for the jib arm carrying the holder. Although the worm gear allows a highly accurate positioning of the anti-skid device, its outlay in terms of production is nevertheless comparatively high. Particularly on vehicles with compressed-air braking systems, therefore, simpler pivoting units actuable by compressed air, such as are known, for example, from EP 0,162,823 B1, are used for preference. In the anti-skid device disclosed in the publication mentioned last, the pivoting unit consists essentially of two disks which are arranged eccentrically on the pivot axle of the jib arm and into which oppositely directed movements can be introduced by two pull cords of Bowden pulls, a compressed-air unit serving for actuating the pull cord transferring the holder out of its position of rest into its operating position, and a compressed-air spring serving for returning the holder from its operating position into the position of rest, the said compressed-air spring being arranged, together with the compressed-air unit, at a point on the vehicle relatively far removed from the pivoting unit and consequently necessitating the use of long Bowden pulls both for connecting the compressed-air unit and for connecting the compressed-air spring to the pivoting unit.